<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }
        .left {
            width: 200px;
            height: 500px;
            background-color: yellow;
            position: absolute;
            /* 绝对定位，使位置固定 */
            left: 0;
            top: 0;
        }
        .center {
            height: 600px;
            background-color: purple;
            margin: 0 300px 0 200px;
            /* 通过外边距确定宽度 */
        }
        .right {
            width: 300px;
            height: 500px;
            background-color: red;
            position: absolute;
            /* 绝对定位，使位置固定 */
            right: 0;
            top: 0;
        }
    </style>
</head>

<body>
    <div class="left"></div>
    <div class="center"></div>
    <div class="right"></div>
</body>
<script>

</script>
</html>